Module java.desktop
Package java.awt.font

Class FontRenderContext

java.lang.Object
java.awt.font.FontRenderContext
public class FontRenderContext
extends Object
The FontRenderContext class is a container for the information needed to correctly measure text. The measurement of text can vary because of rules that map outlines to pixels, and rendering hints provided by an application.

One such piece of information is a transform that scales typographical points to pixels. (A point is defined to be exactly 1/72 of an inch, which is slightly different than the traditional mechanical measurement of a point.) A character that is rendered at 12pt on a 600dpi device might have a different size than the same character rendered at 12pt on a 72dpi device because of such factors as rounding to pixel boundaries and hints that the font designer may have specified.

Anti-aliasing and Fractional-metrics specified by an application can also affect the size of a character because of rounding to pixel boundaries.

Typically, instances of FontRenderContext are obtained from a Graphics2D object. A FontRenderContext which is directly constructed will most likely not represent any actual graphics device, and may lead to unexpected or incorrect results.

See Also:
RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.KEY_FRACTIONALMETRICS, Graphics2D.getFontRenderContext(), LineMetrics

  • Constructor Summary

    Constructors 
    Modifier Constructor Description
    protected FontRenderContext()
    Constructs a new FontRenderContext object.
      FontRenderContext​(AffineTransform tx, boolean isAntiAliased, boolean usesFractionalMetrics)
    Constructs a FontRenderContext object from an optional AffineTransform and two boolean values that determine if the newly constructed object has anti-aliasing or fractional metrics.
      FontRenderContext​(AffineTransform tx, Object aaHint, Object fmHint)
    Constructs a FontRenderContext object from an optional AffineTransform and two Object values that determine if the newly constructed object has anti-aliasing or fractional metrics.

  • Method Summary

    Modifier and Type Method Description
    boolean equals​(FontRenderContext rhs)
    Return true if rhs has the same transform, antialiasing, and fractional metrics values as this.
    boolean equals​(Object obj)
    Return true if obj is an instance of FontRenderContext and has the same transform, antialiasing, and fractional metrics values as this.
    Object getAntiAliasingHint()
    Return the text anti-aliasing rendering mode hint used in this FontRenderContext.
    Object getFractionalMetricsHint()
    Return the text fractional metrics rendering mode hint used in this FontRenderContext.
    AffineTransform getTransform()
    Gets the transform that is used to scale typographical points to pixels in this FontRenderContext.
    int getTransformType()
    Returns the integer type of the affine transform for this FontRenderContext as specified by AffineTransform.getType()
    int hashCode()
    Return a hashcode for this FontRenderContext.
    boolean isAntiAliased()
    Returns a boolean which indicates whether or not some form of antialiasing is specified by this FontRenderContext.
    boolean isTransformed()
    Indicates whether or not this FontRenderContext object measures text in a transformed render context.
    boolean usesFractionalMetrics()
    Returns a boolean which whether text fractional metrics mode is used in this FontRenderContext.

    Methods declared in class java.lang.Object

    clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • FontRenderContext

      protected FontRenderContext()
      Constructs a new FontRenderContext object.

    • FontRenderContext

      public FontRenderContext​(AffineTransform tx, boolean isAntiAliased, boolean usesFractionalMetrics)
      Constructs a FontRenderContext object from an optional AffineTransform and two boolean values that determine if the newly constructed object has anti-aliasing or fractional metrics. In each case the boolean values true and false correspond to the rendering hint values ON and OFF respectively.

      To specify other hint values, use the constructor which specifies the rendering hint values as parameters : FontRenderContext(AffineTransform, Object, Object).

      Parameters:
      tx - the transform which is used to scale typographical points to pixels in this FontRenderContext. If null, an identity transform is used.
      isAntiAliased - determines if the newly constructed object has anti-aliasing.
      usesFractionalMetrics - determines if the newly constructed object has fractional metrics.

    • FontRenderContext

      public FontRenderContext​(AffineTransform tx, Object aaHint, Object fmHint)
      Constructs a FontRenderContext object from an optional AffineTransform and two Object values that determine if the newly constructed object has anti-aliasing or fractional metrics.
      Parameters:
      tx - the transform which is used to scale typographical points to pixels in this FontRenderContext. If null, an identity transform is used.
      aaHint - - one of the text antialiasing rendering hint values defined in java.awt.RenderingHints. Any other value will throw IllegalArgumentException. VALUE_TEXT_ANTIALIAS_DEFAULT may be specified, in which case the mode used is implementation dependent.
      fmHint - - one of the text fractional rendering hint values defined in java.awt.RenderingHints. VALUE_FRACTIONALMETRICS_DEFAULT may be specified, in which case the mode used is implementation dependent. Any other value will throw IllegalArgumentException
      Throws:
      IllegalArgumentException - if the hints are not one of the legal values.
      Since:
      1.6

  • Method Details